> Jens Axboe <[EMAIL PROTECTED]> writes:
>
> > On Wed, Mar 22 2000, Florian Weimer wrote:
> > > Is it possible to use a standard SCSI host adapter to fake other SCSI
> > > devices on the same bus (for example, an additional hard disk with a
> > > SCSI ID different from that of the host adapter)? If the answer is
yes,
> > > can I use the current "generic" user-space SCSI interface for that?
> > >
> > > (This sounds crazy, I know, but I think I'd have an interesting
> > > application for this stuff...)
I have built 2 "Fake SCSI" device drivers so far. First one was for PC's
on
DOS, latest was for an RS/6000 on AIX.
Not only does the hardware have to have Target capabilities, you will most
likely have to rewrite some of the adapter firmware to behave as a target
(you have to "wait on selection" vs. "wait on reselection" or actually
doing a select). If your adapter has a programmable SCSI chip (I used
the NCR 53C8x and a 53c720) you have a starting point.
Both applications required custom device drivers and a specialized
application
on top of the DD. Its a non-trivial task to _fully_ emulate a SCSI Target.
Relatively "dumb" devices like tape drives are much easier than a disk
drive.
(My "fake tape" had the worlds fastest response to a "rewind" cmd!!!)
Personally it was a very fun project, but definitely not a quickie. Crude
function can be brought up fairly fast, but all the error handling and the
permutations brought on by different Mode Select settings will have you
frowning at the keyboard for awhile.
Regards,
Steve Buller
disclaimer: My thoughts are my own (or paraphrases of the voices in my
head) and not those of my employers.
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